1. Field of the Invention
This invention relates generally to containers housing a pressurized medium such as self-chilling or self-heating food and beverage containers and more particularly to an improved heat exchange unit which is housed within a self-cooling container for cooling a product such as a food or beverage wherein the heat exchange unit is secured within the container and houses the pressurized medium.
2. Description of Prior Art
It has long been desirable to provide a simple, effective and safe device which may be housed within a container such as a food or beverage container for the purpose of cooling or heating a product such as food or beverage on demand. With respect to self-cooling containers, various types of devices have been developed to accomplish such desired self-cooling and various types of refrigerants have been disclosed for accomplishing such cooling. The refrigerant devices may be chemical, electrical, and may include gaseous reactions and the like. Typical of such devices are those disclosed in U.S. Pat. Nos. 2,460,765; 3,373,581; 3,636,726; 3,726,106; 4,584,848; 4,656,838; 4,784,678; 5,214,933; 5,285,812; 5,325,680; 5,331,817; 5,394,703; 5,606,866; 5,692,381; 5,692,391; 5,655,384; 6,102,108; 6,105,384; and 6,125,649.
Self-cooling devices utilized in the prior art exemplified by the above-identified patents are generally unsatisfactory. Some of the difficulties which have been encountered are that the devices generally rely on toxic or environmentally unfriendly chemicals, require very bulky pneumatic circuits and cannot economically be used in small containers such as beverage cans or food cans, are rather complex, and thus are expensive to manufacture and maintain and are ineffective. In addition, it has been found that if the pressure within the heat exchange unit increases to a predetermined amount, the portion of the heat exchange unit which carries the dispensing valve may be stressed to such a degree that it moves thereby causing the heat exchange unit to rupture and become unusable, or in the worst case, results in a total failure of the container.
Referring now more particularly to FIGS. 1, 2 and 3, there are illustrated three different embodiments of prior art containers within which there is disposed a heat exchange unit (HEU) for cooling a beverage contained within an outer container.
As shown in FIG. 1, the container (10) includes a heat exchange unit 924) disposed therein and which is surrounded by a beverage (26) to be cooled. The container includes a lid 918) which includes a conventional pull tab (12), secured to a panel (14) such that when the pull tab (12) is lifted, the panel 914) is bent into the container (10). The operation of tab (12) extending the tear panel (14) into the container (10) is well known in the art. The lid (18) conventionally includes an angular ridge (20) which is clamped to the top end (22) of the container (10). The HEU (24) houses a cooling medium which under various circumstances can increase in pressure and if the pressure becomes high enough the upper portion 928) of the HEU (24) which includes the crimp (30) that secures the valve (32) to the HEU may expand or rupture, thus creating an ineffective apparatus.
FIG. 2 is another prior art container (40) having an HEU (50) disposed internally thereof to be surrounded by a beverage (42) which is to be cooled. The top of the beverage container (44) as shown at (46) has the conventional pull tab (48) as above described. The HEU (50) includes a dispensing valve (52) secured to the cap (54) which is fitted over the top of the HEU (50) and is secured thereto. The valve (52) is carried by the skirt or flange (54) which is held in place by being crimped over the top (56) of the cap (54). The protective cover (58) is placed over the activating stem of the valve (52) to protect it from inadvertent activation. The HEU (50) and the valve (52) are secured to the bottom (62) of the can (44). Again if over pressure within, the pressurized medium contained internally of the HEU (50) occurs, rupture between the cap (54) and the body of the HEU (50) will result rendering the device unusable.
Referring now particularly to FIG. 3, there is shown still another embodiment of a prior art beverage cooling container (112) which includes an HEU (120) having internally thereof an adsorbent (138) which in the preferred embodiment is an activated carbon which receives carbon dioxide under pressure which is inserted through the valve mechanism (124) to enter into the internal part of the HEU through the opening (128) to be adsorbed by the carbon. The valve (124) is held in place by flange (122) which is crimped to the necked in top portion (132) of the HEU (120). A protective cover 150 is placed over the activating stem (130) of the valve (124) to protect it from inadvertent activation. When the activating stem (130) is depressed, the carbon dioxide is desorbed from the carbon to cool the beverage (114). The top (116) of the container (112) includes the typical pull tab (not shown) as above described. Again if the pressurized carbon dioxide contained internally of the HEU (120) over pressurizes, the necked in portion (134) of the HEU (120) will move outwardly causing a release of the valve rendering the device unusable.
What is needed, therefore, is a device which may be seated in a container and function as a HEU for cooling the contents of the container such as a food or beverage which is simple, effective and safe, even under relatively high pressure situations.